This is probably not going to make either of you feel any better right now, but I have been following this thread for a long time now and 4-5 months off invega is not that long in the grand scheme of things. It's still relatively early in the recovery process. But over time you will definitely keep noticing that you recover more and more as the months go on. I know that doesn't help right now, but perhaps it might give you guys a bit of hope?
Yes you are right, the main theory of schizophrenia that psychiatrists refer to is the dopamine theory, which says that the mainly problematic symptoms of schizophrenia e.g. hallucinations, delusions, paranoia etc, are caused by too much dopamine in one particular area of the brain called the nucleus accumbens. Antipsychotics such as invega are meant to significantly reduce the amount of dopamine released in this area of the brain. We could get much more technical about it, of course, but that is the basic theory.
The brain is incredibly awesome at repairing itself over time, by neuroplasticity, so in theory the damage should not be permanent at all. So it's just a matter of WHEN your brain recovers, not IF.